The field of the invention comprises generally producing pile textiles including carpet, upholstery, and apparel fabrics, in which the pile loops or cut pile yarns of different colors are distributed spatially either in a predetermined pattern or in a random manner.
The prior art teaches the technique of coloring pile forming yarns by printing a pattern of the same or differently colored segments upon a sheet of yarns, followed by the formation of pile in a backing sheet usually by tufting the yarns and to a lesser extent by a form of knitting. The yarns pass through a printing station having means to print the same or different colored dye liquors upon segments of the yarn which are of predetermined sequence of length, the pattern repeating itself at well-spaced intervals to produce the desired pattern or random effect in the finished material. The dyed yarns are wound up on storage means such as cones or beams at some stage prior to the formation of the pile. In subsequent steps, the yarn storage means are shuffled to separate adjacently printed yarns and loaded into a creel or beam associated with a standard multi-needle tufting machine or some other suitable pile-forming machine.
The earlier methods disclose certain difficulties (and at this point reference is made to U.S. Pat. No. 3,447,215 dated June 3, 1963, and U.S. Pat. No. 3,621,780 dated Nov. 23, 1971, John G. Tillotson being the inventor of both) in that regardless of whether a random pattern as set forth in said patents is to be accomplished, or a final ordered pattern is to be accomplished in the final carpet or fabric, difficulty has been experienced in maintaining uniformity in the dyeing of the individual yarns that form the web or sheet of such yarns.
The dyeing of yarns, that is, the receptivity and effect of dyes on yarns, is governed to a great extent by the past history of the yarn itself. The more uniform the past history of the yarns forming a sheet of yarns prior to printing thereof, the more uniform said yarns will be colored prior to entering a tufting machine, for example. It has been found that yarns differ somewhat in their prior history, and therefore, the color of the yarns in a sheet thereof is not as uniform as can be desired.
Particularly is this is true if a crimp or additional configuration or "memories" are established in the yarns prior to the dyeing operation. Also, the stresses in a yarn have an effect on the molecular orientation or disorientation within the fiber itself, and the orientation of the fibers in a yarn end. As a result, it has been found in practice that it is not an easy matter to obtain a desired random pattern or a desired ordered pattern in the final tufted or knitted material.